JavaScript Global Object & Standard Global Functions Quiz

Review

1. What does globalThis provide?

   globalThis is the standardized way to access the global this value.
2. Which declaration belongs to the declarative part of a Global Environment Record?

   Lexical declarations use the declarative component.
3. What is special about direct eval?

   Direct eval receives special scope treatment; indirect eval does not.
4. Why can isFinite("42") be true?

   The global isFinite performs numeric coercion before testing finiteness.
5. What is the important distinction between isNaN and Number.isNaN?

   The global function applies ToNumber; Number.isNaN requires a Number NaN value.
6. What does parseInt("ff", 16) return?

   The hexadecimal digits ff represent decimal 255.
7. What does parseInt("42px", 10) demonstrate?

   parseInt accepts the longest leading prefix valid for the selected radix.
8. What does parseFloat("3.5rem") return?

   parseFloat parses the leading decimal numeric portion.
9. Which function is intended for a single URI component?

   encodeURIComponent treats the input as one URI component.
10. Which decoder matches encodeURI?

    decodeURI is the corresponding complete-URI decoder.
11. What does encodeURIComponent(123) do first?

    The encoding operation stringifies its argument.
12. What can malformed percent-encoded input cause during URI decoding?

    Malformed URI escape or UTF-8 input causes URIError.
13. How should escape and unescape be classified?

    They are legacy Annex B global additions.
14. Where should Array and Map semantics be taught?

    The global object is an access surface; domain semantics stay with their owning lessons.
15. Which statement is correct?

    ECMAScript standardizes globalThis while hosts provide additional environment-specific globals.
16. What is the appropriate role of eval in the curriculum?

    eval is a source-evaluation feature, not a general data or module mechanism.